is there any point of going 2.0? i just blew my motor (a ring or piston) and wann bore it out to a 2.0 and wasondering is there any point of doing it. im not sure wats the mm but its a bit over 1.8. i have darton sleeves.

 

It should give you more torque.

Eric

 

The point in doing it is more torque.

I was thinking of doing it also but :

-Consume more gas.
-I head that it is easier to warp and could hurt your rings.

There was a thread on someone who make 600+ horsepower with stock bore.

If you want more torque, maybe get ls/vtec?

 

I'm in the same boat right now. I have my sleeved block and need to buy pistons asap. I'm trying to decide if I want to go with a 81.5mm bore so I can get head gaskets locally just in case. I would love to run a 84.5 bore for the extra displacement but I could just run 2psi extra and make up for it. Also wonder about head gasket sealing with a larger bore. I may just end up going with a 83mm bore and just be happy. Say a b18c motor makes 300whp/240tq@ 13psiwith a 81mm bore any guesses what the same motor would make with a 84.5 bore? Any guesses? 330/270?

 

I have a b18c with a 84mm bore, which is just under a 2.0L. This weekend i made 337whp at 15psi with a conservative tune. Not to sure of the TQ. I havn't had any problems so far.

 

what turbo and trim sizes?

 

prescision sc52, details on setup in sig.

 

The only way to make 400whp on pump gas is a 84.5mm bore. I should see a bit over 400whp on pump, with my 2.0L gsr with the extensive amount head work, manifold, etc.

 

With a 84.5mm bore is there ever problems with head gasket sealing? I'm guessing the differance between a 1.8 and a 2.0 would almost be the same as a 1.6 to a 1.8 but not quite. Will increasing bore help more with hp or tq? Or both equally?

 

A bigger bore will increse TQ which in turn will also increase HP

 

I am gettin a JG Pro Series Head. I really dont know much about it, but its coming with my block.

How much difference will this make in my numbers vs a stock head?

 

There is no problems with the headgaskets sealing at all. I am running a 86mm GE sleeved gsr block for an all motor application. There isnt going to be any issues on that either. Also, another aspect of the bigger bore is that the fuel mixture has larger area to expand upon. In theory you'll get a better swirl mixture. There are debates on spot facing the head to 84.5mm or keeping it 81mm. I kept the stock 81mm, mainly because I believe that the mixture is "forced" into the center of the piston creating a better disapation of the fuel/air mixture. There is the other theory that the head creates a lip in the combustion chamber that acts as a giagantic hot spot for detonation. Before I installed my head I sanded down the sharp edges of the combustion chamber, so they were rounded instead of coming to a point. It should help. Both theories are technically correct, I'll see which one wins.


[Modified by boosted hybrid, 12:33 AM 4/1/2003]

 

honda or cometic head gasket?

 

GE/OEM honda overbored headgasket. They are 30.00 more than honda gets for them, but they are overbored to perfection. When installing the head to the block use their headgasket in the bore size you are running (unless stock, then just run OEM). Use copper spray. Torque down the headstuds to 22, then 55, then 82 ft-lbs. After each torque spec, retorque before moving onto the next spec. After you torqued them down to 82 ft-lbs, wait a few hours then torque them again. After 10 heat cycles, torque them again. Follow that to the tee and it will seal with no problems.

 

Does anything need to be done to the head to take full advantage of the larger bore? Oversized valves, port & polish?

 

What CR are you running?

 

Probably want to open up the combustion chamber to match the bore size.

 

Why not 84.5 AND 2psi extra?

 

Nothing needs to be done to the head, but you can make significant more power if you run larger valves and higher lift cams. I am running .5mm on the intake side, .5mm on the exhaust side of the head. I am also running ef1.com m21 FI cams with 11.7 lift on them. They will work great as a system, and let the larger bore get more air to fill the larger volume. I can't comment on exactly how much power it will add, but it adds to the overall efficiency of the head.

As far as spot facing the head to the bore size, you really dont need to. Here is a pic of my head I got back from portflow for my all motor application. It was P&P'd, ferrea .5mm oversized valves, skunk2 springs, retainers and spot faced to 86mm which is the bore of my all motor engine.



My only reasoning behind getting the head spotfaced is the engine is running 13.5:1 compression. If any detonation will occur, its going to be on a super high compression engine like mine.

 

I so cant wait to see what you put down!

 

I'm having 1mm oversized intake valves installed in my head will this hurt performance with stock exhaust valves?

 

i would upgrade the exhaust .5mm over and stay with 1mm on the intake that whaat we run on most heads work great that way. it wont hurt performacne but larger exhaust valve will help

 

It shouldnt be to much of an issue. Once you open up the intake, you should run at least .5mm oversized on the exhaust. With 1mm oversized you are going to have to get your valve seats reworked to fit theh larger 1mm size valves. If you having a head shop do your head, I am sure that they know to rework the valve seats.

My motivation to running aftermarket valves is much the same for running forged pistons. I have had one engine melt some valves, it wasnt pretty. When you are pushing serious psi the stock valves can go, much the same as the stock pistons. It doesnt happen very often, but it can. I did the valves more for an insurance thing.

If you look at the import builders 470whp 2.0L engine that they sell, they run extensive amount of head work. The engine makes 470whp on pump gas, which goes to show how much headwork matters. When you are building the head you need to look at everything in terms of a system. The IB heads are very extensive in the amount of work they put into them by portflow, and aftermarket parts. If you are doing the head it starts with the throttle body, ends with the valves. You'll get a significant amount more power if you mod up the head in just the right ways.

 

thats 100% correct. it all starts with a good head work..